The present invention relates to a slide mechanism in a numbering device for an offset press.
In an offset press, a numbering device may or may not be used dependent on whether numbers are to be printed or not. However, the conventional numbering device cannot readily be attached to and detached from the offset press (hereinafter referred to as the "main machine"). Thus, it is highly troublesome to change between operations where numbers are printed and numbers are not printed. Moreover, when the numbering device is not in use, paper is still passed therethrough and the numbering device is still required to be driven, imposing a large load on the main machine and accelerating wear of the numbering device.
Further, small-size offset presses are generally constructed so as to pass sheets longitudinally therethrough. When printing numbers on trailing ends of sheets with a numbering device subsequent to an ordinary printing operations, sheets tend to be displaced or slackened since they are gripped only when they reach a position where numbering and numbering impression cylinders of the numbering device contact each other at their peripheries. With such an arrangement, the printed numbers on the trailing ends of the sheets are liable to be out of precise alignment with each other. The sheets are therefore required to be held down by brush rollers or the like. However, such a sheet holder arrangement fails to be fully effective.
FIG. 1A of the accompanying drawings illustrates a cylinder arrangement proposed to solve the above problems. In FIG. 1A, a gripper (not shown) is mounted on a numbering impression cylinder b held in peripheral contact with a numbering cylinder a for discharging sheets directly from the numbering impression cylinder b. With such a cylinder arrangement, the gripper is opened at a point c on the numbering impression cylinder b to discharge sheets d, whereupon the sheets d are released. Therefore, the trailing ends of the sheets cannot be prevented from being displaced.